The food and pharmaceutical industries have recently focused attention on polyol polyesters for use as low calorie fats in food products and as pharmaceutical agents, e.g., for the lowering of blood cholesterol levels. U.S. Pat. No. 3,600,186, Mattson and Volpenhein, issued Aug. 17, 1971, describes low calorie food compositions formed by replacing at least a portion of the fat content of food products with higher polyol fatty acid polyesters. U.S. Pat. No. 3,954,976, Mattson and Volpenhein, issued May 4, 1976, describes pharmaceutical compositions for inhibiting the absorption of cholesterol comprising effective unit dosage amounts of higher polyol fatty acid polyesters, as well as the method for treating hypercholesterolemia using these polyesters. Additional pharmaceutical uses are described in U.S. Pat. No. 4,241,054, Volpenhein and Jandacek, issued Dec. 23, 1980 (removal of halogenated toxins from the body), and U.S. Pat. No. 4,264,583, Jandacek, Apr. 28, 1981 (treatment of gallstones).
As a result of these many uses for the higher polyol fatty acid polyesters, it would be desirable to have an efficient high yield synthesis for them. Historically, such syntheses have been conducted using a mutual solvent to solubilize a polyol and esters of long chain fatty acids, thus providing a homogeneous reaction medium suitable for catalytic transesterification. One variation of this process, known as the Snell synthesis, has been employed as a means for preparing both poly- and lower esters. However, the solvents employed in such processes are difficult to separate from the final product and are characteristically toxic, therefore limiting the usefulness of such syntheses in the food and pharmaceutical industries. Accordingly, efforts have been directed toward the discovery of high yield syntheses of polyol fatty acid polyesters which do not employ toxic solvents.